From patchwork Mon Aug 3 05:04:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 251769 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B13BC433E1 for ; Mon, 3 Aug 2020 05:20:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E93B206DA for ; Mon, 3 Aug 2020 05:20:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbgHCFUt (ORCPT ); Mon, 3 Aug 2020 01:20:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:44020 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726993AbgHCFUs (ORCPT ); Mon, 3 Aug 2020 01:20:48 -0400 IronPort-SDR: K3mMivGNA52ss0IBKjFiqITXZi9YjMwhvfyu9hR4nnpMImH+SNSpkT2lQwSqTZlnPMzxNkK9ol 4ZuiHnaNjgbQ== X-IronPort-AV: E=McAfee;i="6000,8403,9701"; a="170149776" X-IronPort-AV: E=Sophos;i="5.75,429,1589266800"; d="scan'208";a="170149776" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Aug 2020 22:20:48 -0700 IronPort-SDR: RpV/TarlfZtpGTxcGFV/YB86O42UoKDQBjZi2zZhGZ/aMAH3qwe80fGLnen8feyash85FU7j2F Dae5w7PzminA== X-IronPort-AV: E=Sophos;i="5.75,429,1589266800"; d="scan'208";a="273823070" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Aug 2020 22:20:48 -0700 Subject: [PATCH v4 23/23] device-dax: Add a range mapping allocation attribute From: Dan Williams To: akpm@linux-foundation.org Cc: Joao Martins , peterz@infradead.org, vishal.l.verma@intel.com, dave.hansen@linux.intel.com, ard.biesheuvel@linaro.org, vishal.l.verma@intel.com, linux-mm@kvack.org, linux-nvdimm@lists.01.org, joao.m.martins@oracle.com, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, dri-devel@lists.freedesktop.org Date: Sun, 02 Aug 2020 22:04:29 -0700 Message-ID: <159643106970.4062302.10402616567780784722.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <159643094279.4062302.17779410714418721328.stgit@dwillia2-desk3.amr.corp.intel.com> References: <159643094279.4062302.17779410714418721328.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org From: Joao Martins Add a sysfs attribute which denotes a range from the dax region to be allocated. It's an write only @mapping sysfs attribute in the format of '-' to allocate a range. @start and @end use hexadecimal values and the @pgoff is implicitly ordered wrt to previous writes to @mapping sysfs e.g. a write of a range of length 1G the pgoff is 0..1G(-4K), a second write will use @pgoff for 1G+4K... This range mapping interface is useful for: 1) Application which want to implement its own allocation logic, and thus pick the desired ranges from dax_region. 2) For use cases like VMM fast restart[0] where after kexec we want to the same gpa<->phys mappings (as originally created before kexec). [0] https://static.sched.com/hosted_files/kvmforum2019/66/VMM-fast-restart_kvmforum2019.pdf Signed-off-by: Joao Martins Link: https://lore.kernel.org/r/20200716172913.19658-5-joao.m.martins@oracle.com Signed-off-by: Dan Williams --- drivers/dax/bus.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index b984213c315f..092112bba6ed 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -1040,6 +1040,67 @@ static ssize_t size_store(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RW(size); +static ssize_t range_parse(const char *opt, size_t len, struct range *range) +{ + unsigned long long addr = 0; + char *start, *end, *str; + ssize_t rc = EINVAL; + + str = kstrdup(opt, GFP_KERNEL); + if (!str) + return rc; + + end = str; + start = strsep(&end, "-"); + if (!start || !end) + goto err; + + rc = kstrtoull(start, 16, &addr); + if (rc) + goto err; + range->start = addr; + + rc = kstrtoull(end, 16, &addr); + if (rc) + goto err; + range->end = addr; + +err: + kfree(str); + return rc; +} + +static ssize_t mapping_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct dev_dax *dev_dax = to_dev_dax(dev); + struct dax_region *dax_region = dev_dax->region; + size_t to_alloc; + struct range r; + ssize_t rc; + + rc = range_parse(buf, len, &r); + if (rc) + return rc; + + rc = -ENXIO; + device_lock(dax_region->dev); + if (!dax_region->dev->driver) { + device_unlock(dax_region->dev); + return rc; + } + device_lock(dev); + + to_alloc = range_len(&r); + if (alloc_is_aligned(dev_dax, to_alloc)) + rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc); + device_unlock(dev); + device_unlock(dax_region->dev); + + return rc == 0 ? len : rc; +} +static DEVICE_ATTR_WO(mapping); + static ssize_t align_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -1172,6 +1233,8 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) return 0; if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA)) return 0; + if (a == &dev_attr_mapping.attr && is_static(dax_region)) + return 0; if ((a == &dev_attr_align.attr || a == &dev_attr_size.attr) && is_static(dax_region)) return 0444; @@ -1181,6 +1244,7 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n) static struct attribute *dev_dax_attributes[] = { &dev_attr_modalias.attr, &dev_attr_size.attr, + &dev_attr_mapping.attr, &dev_attr_target_node.attr, &dev_attr_align.attr, &dev_attr_resource.attr,